Blob field save AsString into DB

[question]

Hi,
I have a Bolb field 'CollectID' in the DB and i am saving the data into this Blob Field AsString in the following way,

Code:

QueryA.ParamByName('CollectID').AsString := QueryB.FieldByName('CollectID').AsString;

its working fine,but i am not sure is that okay or it can be problem in future